The phone rings, and you answer it. All you hear is dead air. You are finally connected to someone, who turns out to be a telemarketer soliciting for a company with which you have no business relationship.

You’ve registered your landline, fax and cellphone numbers on the federal Do Not Call list. So why are they calling you?

Under the federal Telemarketing Sales Rule some businesses are exempt, including long-distance phone companies, airlines, insurance companies and any company that you have an established business relationship.

The key phrase is established business relationship. You forgot that when you went to your local retailer, the clerk asked you for your phone number for tracking or for a retailer-shopper survey. When you provided your phone number, you have created a relationship. So what do you do?

If you do not want further calls from the business, tell the caller not to call you again and to put you on the company’s do-not-call list. The company or solicitor must honor your request.

To limit telemarketing calls, do not give out your number just because you are asked for it. Find out why the retailer needs it before you disclose it.

More information is available through the Marin County district attorney’s consumer protection unit at 473-6495 or through its website at www.co.marin.ca.us/da.